1596 



THE FILARIASES 



in 1789, gave the first full account we have been able to trace of the develop- 

 ment of elephantiasis of the scrotum, which he clearly recognized to be the 

 same disease as that affecting the legs. He describes and figures an elephan- 

 tiasis of the scrotum 24 inches in height and 6 feet in circumference at its 

 base, and he further notes cases of spontaneous cure by sloughing. In 1809, 

 and again in 1824, Alard wrote most excellent treatises on the elephantiasis 

 of the Arabs. 



In 1 81 2 Chapotin was the first to describe haematochyluria in Mauritius, and 

 he was followed by Salese in 1832, whose paper aroused so much interest 

 in Brazil, where the disease had for long been well known, that in 1835 a 

 conference on the subject was held in Rio de Janeiro, after which there were 

 many investigations, among which may be mentioned those of Rayer in 1838, 

 Quevenne in 1839, Siguad in 1844, and Mozae-Azema in 1858, the last-named 

 observer reporting it in Reunion. In 1854 Jamsetjee described lymph 

 scrotum. The result of all this work was to produce a consensus of opinion 

 among Brazilian, French, and Indian physicians that haematochyluria and 

 elephantiasis were merely different aspects of the same disease, and at the 

 same time the classical researches of Danielssen and Boeck in 1848 on leprosy, 

 and of V. Carter in i860 on mycetoma, ended the confusion of these two 

 diseases with elephantiasis. 



In 1863 Demarquay, in Paris, discovered a Microfilaria in the fluid from a 

 hydrocele in a person who had come from Havana, but this discovery passed 

 unnoticed at the time. In 1866 Wucherer, stimulated by the discovery of 

 Schistosoma hcematobium in haematuria in Egypt, found a Microfilaria in 

 the urine of a case of haematuria in Brazil, but at first thought it to be of no 

 importance; but when, after two years of careful work, he regularly found the 

 same small worm in the urine of persons suffering from haematochyluria, he 

 published his discovery in 1 868, in the same year in which Lewis independently 

 found the same parasite in the urine of a case of chyluria in India. Lewis 

 also found the same small worm in the blood and lymph of persons suffering 

 from elephantiasis of the leg, and concluded that it was the cause of the 

 chyluria and the elephantiasis. In 1 876 Winckel found the same small parasite 

 in the fluid from a case of chylous ascites. 



In 1876-77 Bancroft discovered adult female worms in a lymphatic abscess 

 in the arm, and in a hydrocele of the cord, and these worms were later de- 

 scribed by Cobbold, who gave them the name Filaria bancrofti. About the 

 same time Manson found the Microfilarics in the lymph from the enlarged 

 lymphatics of a lymph scrotum and from varicose lymphatic glands, and 

 suspected that the so-called malarial orchitis must be of filarial origin. He 

 also obtained a female worm from a case of elephantiasis of the scrotum, 

 and in 1879 Lewis found pieces of male and female worms; while in 1888 

 Sibthorpe obtained perfect specimens of a male and female from a lymph 

 scrotum, the former being described by Bourne. Lastly, in 1898, Maitland 

 drew attention to the occurrence of synovitis in cases of filariasis, which he 

 considered could not be looked upon as accidental, and must be held to be 

 of filarial origin, but this view cannot be regarded as proved. 



In this way arose the knowledge that the causation of a form of lym- 

 phangitis, of lymphatic abscesses, of varices of lymphatics, and of lymph 

 glands, of haematochyluria, of chylous extravasations, and of elephantiasis, 

 was the invasion of the body by Filaria bancrofti Cobbold, 1877. 



In the meanwhile the epoch-making discovery of the agency of the mos- 

 quito in the dissemination of Filaria bancrofti was made by Manson in 1878, 

 as well as the periodicity of the MicrofilaricB, which only appear in the blood 

 in large numbers at night, and in 1899 he discovered that they retire to the 

 vessels of the lungs during the day. With regard to this periodicity, Bahr has 

 shown that it does not depend upon the human host, but upon the habits of the 

 insect host being nocturnal when the host is Culex fatigans, and nocturnal and 

 diurnal when the host is Stegomyia pseudo-scutellaris , which is a day-feeding 

 mosquito. Thorpe's view with regard to the diurnal and nocturnal periodicity 

 is that it is caused by the irregular habits of the human hosts, but this latter 



